Since you're asking specifically about the Red and Blue Lines, I guess you've already checked such easy to get and recent books with (quite good, even if not perfect) maps of fortifications in Tobruk like Operation Compass, or Tobruk, 1941?

A very good alternative (more detailed map, but b&w only) is available in Tank Combat in North Africa, on p120.

Curiously, most of such and similar publications have good maps for the eastern side of the 'fortress' only, because that's where Rommel attempted it at first, in April and May 1941. But, 'Tobruk 1941' contains

• not only a detailed map of the Red Line between R24 and R58 (p47), but also

• quite a few photos of various Australian positions from 1941;

• a very nice, '3D' diagram of a 'typical perimeter post' from Ras el-Madauur area (p54; which, I guess, would be exactly what you're looking for);

• and another very detailed map of the complete Red Line (p59).

Sadly, data, photos, diagrams etc. of the Blue Line appear to be very rare. Few years ago, while researching for a map I drew for a related war game, I think to recall to have found some photos online, primarily on the website of the Australian War Museum. Sorry, can't recall any of links, though.